Such synchronizer rings must be centered relative to the synchronizer hub of the manual transmission, in order to ensure a safe and low-wear operation of the synchronization unit. The radial centering of the synchronizer ring relative to the synchronizer hub is effected by the centering collar which can rest against the synchronizer hub.
Such synchronizer rings usually are manufactured from a flat sheet by a stamping and drawing method with a succeeding forming step. The centering collar only is formed by the forming step, namely in that in the sheet-metal cone the first sheet portion is integrally molded by a tool, whereby the centering collar is obtained in the second sheet portion by material forming.
To enable the centering collar to ensure effective centering at any time, the centering collar must have a sufficient collar thickness at least in the second sheet portion or, in other words, the centering collar must be sufficiently high. The material for forming the centering collar however chiefly is removed from the first sheet portion, so that an increase of the collar thickness and hence of the centering collar is not easily possible without too much weakening the sheet-metal cone in the first sheet portion.
Correspondingly, it is the object of the invention to provide a synchronizer ring for a synchronization unit and a method for manufacturing a synchronizer ring, in which the second sheet portion can reliably be designed with a high collar thickness without the sheet-metal cone being excessively weakened in the first sheet portion.